The present invention relates to a device for the spray-coating of objects which are moved past the spray coating device. The device of the invention is preferably used as a so-called "roof machine" for the automatic coating of the front, roof and rear surfaces of automobile bodies with paint, normally enamel. The automobile bodies are transported past the device on a conveyor belt.
Such a roof machine is known from Federal Republic of Germany OS 39 11 454 A1. The machine includes a roof beam which extends horizontally and transversely over the conveyor belt. The beam is provided with spray coating atomizers. The roof beam is supported on two vertical columns. One column contains drive elements for the roof beam and the atomizers. The other column contains paint supply means for supplying the atomizers with paint. The roof beam is connected to the vertical columns via crank-like levers so that the roof beam can be moved upward and downward and can have rotary movement around its longitudinal axis. The atomizers are jointly movable back and forth, are tiltable and are adjustable individually with respect to their lateral distances apart. Particularly when devices of this type are used as roof machines for automatically coating automobile bodies, they spray the paint or enamel from containers or pipe lines in optimum quality and quantity onto the objects to be sprayed, particularly automobile bodies. In practice, a large number of problems arise with such machines:
a) economy of the transfer of the paint, particularly the transfer of the paint from atomizers to the object to be coated with minimum loss of paint and minimum expenditure of energy; PA1 b) good coating quality; PA1 c) avoidance of electric voltages which are dangerous or otherwise detrimental; PA1 d) dirtying of the device by particles of paint; PA1 e) rapid change from one type of paint to another without the presence of disturbing residues of the first type of paint (rapid change of paint); PA1 f) consideration of the flow of air in the spray booth in which the device is used; PA1 g) small disturbances of the slight but continuous and laminar flow of air necessary in the spray booth lead to losses of paint on the path of the paint between the atomizer and the object to be coated and cause dirtying of the device; PA1 h) as a roof machine, the device is intended to coat not only the roof but also the front and rear surfaces of the automobile bodies; for this purpose, the atomizers must be moved through spaces between successive automobile bodies and past the bodies and must be directed in different directions of spray; PA1 i) since the automobile bodies are moved on a conveyor belt, the atomizers must be movable toward or transversely to the automobile bodies, depending on where the coating is required; PA1 j) upon a change in or improvement of any of the above mentioned requirements, no other disadvantages may result.
In known devices for automatic spray coating of objects, many of their parts are arranged within the spray booth, which is made necessary by their construction. As a result, the parts are dirtied by paint and this disadvantageously affects the stream of air flowing in laminar form slowly downward in the spray booth.